1. Field of the Invention
The present invention relates to optical measurement systems and methods, and, more particularly, to corneal topography and ocular aberrations measurement systems and methods.
2. Description of Related Art
Wavefront measurement systems are known in the art for measuring ocular aberrations, such as those taught by the assignee of the present invention (e.g., U.S. Pat. No. 6,271,915, the disclosure of which is incorporated hereinto by reference). An exemplary schematic for such wavefront measurements is given in FIGS. 2-6. in the ""915 patent.
It is also known in the art to measure corneal topography (U.S. Pat. No. 5,062,702).
Finally, a system for measuring aberrations of spherical surfaces has been disclosed by M. V. Mantravadi (xe2x80x9cNewton, Fizeau and Haidinger Interferometers,xe2x80x9d Chapter 1, Optical Shop Testing, 2nd ed., D. Malacara, Ed., John Wiley and Sons, 1992). This system comprises a Fizeau-type interferometer.
It is therefore an object of the present invention to provide a system and method for measuring corneal topography.
It is a further object to provide such a system and method that also measures aberrations in the eye.
It is another object to provide such a system and method that share a common element along a portion of the optical path.
It is an additional object to provide a system and method for measuring aberrations in the eye and corneal topography with a unitary preparation.
It is also an object to provide a method for retrofitting an existing system for measuring aberrations of the eye to add a corneal topography measurement feature.
It is yet a further object to provide a method for making a system for measuring corneal topography.
It is yet another object to provide a method for making such a system that also measures aberrations in the eye.
These and other objects are achieved by the present invention, a unitary system and method for measuring both eye aberrations and corneal topography. The system comprises a sensor for receiving wavefront data, a first optical path, and a second optical path. The first optical path comprises means for introducing a collimated incident beam of radiation into the eye and means for directing a wavefront exiting from the eye to the sensor as retinal wavefront data. Means are also provided for determining from the retinal wavefront data aberrations in the optical system.
The second optical path comprises means for introducing the incident beam onto the corneal surface and means for directing a reflected beam therefrom to the sensor as corneal wavefront data. Means are additionally provided for determining from the corneal wavefront data a topography of an corneal surface.
Finally, the system comprises means for switching the incident beam between the first and the second optical path.
The method of the present invention comprises the step of selecting between a first and a second optical path. If the first optical path is selected, a collimated incident beam of radiation is focused adjacent a retina of an eye, and a reflected beam of radiation is transmitted to a sensor as an aberrated wavefront. Next the aberrated wavefront data are analyzed to characterize the aberrations.
If the second optical path is selected, the incident beam is directed to a corneal surface of the eye. The beam reflected from the corneal surface is transmitted to the sensor, and the corneal wavefront data are analyzed to characterize the corneal topography.